1. Field
The presently disclosed subject matter relates to semiconductor light-emitting apparatuses including an optical fiber, in which light emitted from a semiconductor light source is wavelength-converted by a wavelength converting layer, and to vehicle headlights using the semiconductor light-emitting apparatuses. More particularly, the disclosed subject matter relates to reliable semiconductor light-emitting apparatus having a high thermal conductivity and a high workability, which can be used for a vehicle lamp and the like, and to the vehicle headlights using such semiconductor light-emitting apparatuses.
2. Description of the Related Art
Semiconductor light-emitting devices, in which a part of light emitted from a semiconductor light-emitting chip is converted into light having a different wavelength by a wavelength converting layer and in which a mixture light including the light having the different wavelength mixed with the light emitted directly from the semiconductor light-emitting chip is emitted, have been used as a light source for various lighting units. In this case, semiconductor light-emitting apparatuses, in which the semiconductor light-emitting chip may be located at a desired position by using an optical fiber, have also been known.
A conventional vehicle headlight using a semiconductor light-emitting apparatus including a wavelength converting layer and an optical fiber is disclosed in Patent Document No. 1 (Japanese Patent Application Laid Open JP2013-109928). FIG. 13 is a schematic partial side cross-sectional view showing the conventional vehicle headlight using the semiconductor light-emitting apparatus, which is disclosed in Patent Document No. 1.
The conventional vehicle headlight 60 includes: a reflector 65 including a first opening 67 and a second opening located in an opposite direction of the first opening 67; a transparent filter 68 covering the second opening of the reflector 65; an outer lens 62 located in a forward direction of the transparent filter 68; a makeup panel 61 formed in a substantially ring shape, located adjacent the outer lens 62, and surrounding the transparent filter 68; a casing 63 attaching the reflector 65, the makeup panel 61 and the outer lens 62 thereto; a laser light source 64 having a laser light-emitting surface 64A and an optical fiber 64B, including a wavelength converting material, and attached to the reflector 65, and the laser light-emitting surface 64A being exposed from an end of the optical fiber 64B; a ferrule 66 covering the end portion of the optical fiber 64B; and a laser device 69 configured to emit a laser beam, and incorporated into the casing 63, wherein the optical fiber 64B transmits the laser beam toward the laser light source 64, which emits a mixture light mixing a part of light emitted directly from the laser device 69 with light having a different wavelength wavelength-converted by the wavelength converting material using another part of the laser beam emitted directly from the laser device 69, toward the optical lens 62 via the transparent filter 68.
Accordingly, the conventional vehicle headlight 60 may emit the mixture light having a substantially white color tone from a light-emitting surface of the laser light source 64 toward a road. In the conventional vehicle headlight 60, an amount of heats generated from the wavelength converting material and the laser device 69 may be divided between the laser light source 64 including the wavelength converting material and the laser device 69, which is incorporated into the casing 63, by using the optical fiber 64B. Hence, the conventional vehicle headlight 60 may prevent keeping a large amount of the heat in a space between the reflector 65 and the transparent filter 68, and therefore may improve reliability thereof.
However, in such a structure, in which the laser light source 64 is attached to the reflector 65 in an inward direction of the reflector 65 and also the ferrule 66 is attached to the laser light source 64 in an inward direction of the first opening 67 of the reflector 65, when the vehicle headlight 60, which is incorporated into a vehicle moving, vibrates with violence and/or has a big external shock, the laser light source 64 connecting the ferrule 66 may drop out from the reflector 65. Additionally, because the ferrule 66 connecting the optical fiber 64B may widely vibrate in the first opening 67 of the reflector 65 and also the optical fiber 64B may widely swing between the reflector 65 and the casing 63, the ferrule 66 may drop out from the laser light source 64.
Meanwhile, another conventional vehicle headlight using a reliable semiconductor light-emitting apparatus including a wavelength converting layer and an optical fiber is disclosed in Patent Document No. 2 (Japanese Patent Application Laid Open JP2013-1196818). FIG. 14 is a schematic enlarged side cross-sectional view showing a conventional semiconductor light-emitting apparatus having high reliability for the other conventional vehicle headlight, which is disclosed in Patent Document No. 2.
The conventional semiconductor light-emitting apparatus 70 includes: a light source 75 configured to emit an excited light; a holder 77 having an opening 77a, and attaching the light source 75 thereto; an optical fiber 71 having a first end 71a and a second end 71b, which are exposed from the optical fiber 71 to use the first end 71a as an incident surface and to use the second end 71b as a light-emitting surface, and attached into the opening 77a of the holder 77 so that the first end 71a (the incident surface) can receive the excited light emitted from the light source 75; a focusing lens 76 arranged between the light source 75 and the first end 71a of the optical fiber 71; a ferrule 72 covering the second end portion of the optical fiber 71, and attaching the optical fiber 71 thereto; a wavelength converting material 74 contacting the second end 71b (the light-emitting surface) of the optical fiber 71 and the ferrule 72; a supporter 73 having a light-emitting opening 73a formed in a substantially ring shape, attaching the ferrule 72 and the wavelength converting material 74 thereto, and the light-emitting opening 73a exposing a part of the wavelength converting material 74 from the supporter 73, and facing the first end 71b of the optical fiber 71 via the part of the wavelength converting material 74.
According to the conventional semiconductor light-emitting apparatus 70, the excited light emitted from the light source 75 can be transmitted from the incident surface (71a) of the optical fiber 64B toward the light-emitting surface (71b) of the optical fiber 64B via the focusing lens 76, and can become a mixture light mixing a part of the excited light emitted from the light source 75 with light having a different wavelength wavelength-converted by the wavelength converting material 74 using another part of the excited light. Therefore, the semiconductor light-emitting apparatus 70 can emit the mixture light having a substantially white color tone from the light-emitting opening 73, which exposes the part of the wavelength converting material 74 from the supporter 73
When the semiconductor light-emitting apparatus 70 is used as a light source device for a vehicle headlight, an amount of heats generated from the wavelength converting material 74 and the light source 75 can be divided between the supporter 73 attaching the wavelength converting material 74 thereto and the holder 77 attaching the light source 75 thereto, which can also operate as a radiator, respectively. Accordingly, the vehicle headlight using the light-emitting apparatus 70 can also prevent keeping a large amount of the heat in a lamp house thereof, and therefore may improve reliability thereof.
When each of the above-described semiconductor light-emitting apparatuses shown in FIG. 13 and FIG. 14 is used as a light source device for the vehicle headlight, the light-emitting surface of each of the semiconductor light-emitting apparatuses requires to be attached at a prescribed position of the vehicle headlight to provide a favorable light distribution pattern for drivers, respectively. However, the vehicle headlight may be extremely big as compared with the light-emitting surface of each of the semiconductor light-emitting apparatuses, and the optical fiber connecting the light-emitting surface may be very thin (e.g., diameter of several millimeters) and may be flexible.
Therefore, it may be difficult to attach the light-emitting surface at the prescribed position of the vehicle headlight along with the optical fiber, etc. When a misalignment of the light-emitting surface occurs with respect to the prescribed position of the vehicle headlight, the vehicle headlight may not provide the favorable light distribution pattern for the drivers. Accordingly, the light-emitting surface should require to be attached at the prescribed position of the vehicle headlight in an accurate fashion to always provide the favorable light distribution pattern for the drivers. Additionally, the light-emitting surface should require to be attached at the prescribed position of the vehicle headlight with confidence so that the optical fiber and the like cannot drop out from the vehicle headlight, even when the vehicle headlight vibrates with violence and/or has a big external shock.
The above-referenced Patent Documents and additional Patent Documents are listed below, and are hereby incorporated with their English abstracts in their entireties.
1. Patent Document No. 1: Japanese Patent Application Laid Open JP2013-109928
2. Patent Document No. 2: Japanese Patent Application Laid Open JP2013-196818
3. Patent document No. 3: U.S. Pat. No. 9,076,952
The presently disclosed subject matter has been devised to consider the above and other problems, features, and characteristics in the conventional art devices. Embodiments of the disclosed subject matter can include reliable semiconductor light-emitting apparatuses that can emit a mixture light having favorable optical characteristics and a high workability, which can include an optical fiber and a wavelength converting layer, and which can be used for a vehicle lamp and the like, and. Accordingly, the semiconductor light-emitting apparatuses can emit the mixture light including a substantially white color tone having a high intensity from a small light-emitting surface, which can be used for lighting units such as a vehicle headlight that controls light emitted from the semiconductor light-emitting apparatus using a reflector and/or a projector lens. The disclosed subject matter can also include a vehicle headlight using the semiconductor light-emitting apparatuses with a simple structure, which provide a favorable light distribution pattern for drivers.